A VIRTUAL HEADSTICK FOR PEOPLE WITH SPINAL-CORD INJURIES

This paper presents a virtual headstick system as an alternative to th e conventional passive headstick for persons with limited upper extrem ity function. The system is composed of a pair of kinematically dissim ilar master-slave robots with the master robot being operated by the u ser's head. At the remote site, the end-effector of the slave robot mo ves as if it were at the tip of an imaginary headstick attached to the user's head. A unique feature of this system is that through force-re flection, the virtual headstick provides the user with proprioceptive information as in a conventional headstick, but with an augmentation o f workspace volume and additional mechanical power. This paper describ es the test-bed development, system identification, bilateral control implementation, and system performance evaluation.